I want to learn while looping :P I just cant take my head to it :(

nice different take on it jaytea
only thing is you forgot the Go! after it hits 1

let's toss another method into the mix:

on *:text:!countdown &:#:{
  if ($2 isnum 1-10) && (!$timer(count)) {
    .timercount $2 1 msg # $!calc($timer(count).reps + 1)
  }
}

um TochA1551 you are missing a closing bracket.
Here is 4 different versions of it.

these are working examples only:

This one the trigger is !countdown <number 1-10>
you can do a countdown from any numbers from 1-10
Ex:

<~napa182> !countdown 4
<&Masonic> Countdown started!
<&Masonic> 4
<&Masonic> 3
<&Masonic> 2
<&Masonic> 1
<&Masonic> Go!

on $*:text:/^!countdown\s(\d+)$/iS:#: {
  if (!%count && $regml(1) isnum 1-10) { inc -u10 %count
    msg # 1,9Countdown started!
    var %a = $v1, %b = 1
    while (%a >= 0) {
      $+(.,timerc,%b) 1 %b msg # $iif(%a = 0,Go!,%a)
      dec %a
      inc %b
    }
  }
}

Second one is almost like the one the author posted without the error messages. It counts down from 5.
Trigger is !countdown
Ex:

<~napa182> !countdown
<&Masonic> Countdown started!
<&Masonic> 5
<&Masonic> 4
<&Masonic> 3
<&Masonic> 2
<&Masonic> 1
<&Masonic> Go!

on $*:text:/^!countdown$/iS:#: {
  if (!%count) { inc -u10 %count
    msg # 1,9Countdown started!
    var %a = 5, %b = 1
    while (%a >= 0) {
      $+(.,timerc,%b) 1 %b msg # $iif(%a = 0,Go!,%a)
      dec %a
      inc %b
    }
  }
}

This one is like the one the author posted with the error messages
Trigger is !countdown 5
Ex:

<~napa182> !countdown 4
<&Masonic> Sorry napa182, but max countdown number for me is 5!

<~napa182> !countdown
<&Masonic> Sorry napa182, but you need to type !countdown 5

<~napa182> !countdown 99
<&Masonic> Sorry napa182, but max countdown number for me is 5!

<~napa182> !countdown 5
<&Masonic> Countdown started!
<&Masonic> 5
<&Masonic> 4
<&Masonic> 3
<&Masonic> 2
<&Masonic> 1
<&Masonic> Go!

on $*:text:/^!countdown?\s?(\d+)?$/iS:#: {
  if (!%count) { inc -u10 %count
    if ($regml(1) != 5 || !$regml(1)) { 
      msg # 1,12Sorry 13,12 $nick $+ , 8,12but $iif(!$regml(1),$&
        you need to type !countdown 5,max countdown number for me is 5!)
    }
    else {
      msg # 1,9Countdown started!
      var %a = 5, %b = 1
      while (%a >= 0) {
        $+(.,timerc,%b) 1 %b msg # $iif(%a = 0,Go!,%a)
        dec %a
        inc %b
      }
    }
  }
}

The last one is a version that has 2 different triggers:
Also you can do a countdown from any numbers from 1-10

!countdown <number 1-10> will message the channel
@countdown <number 1-10> will notice the nick

Ex:

<~napa182> @countdown 3
-Masonic- Countdown started!
-Masonic- 3
-Masonic- 2
-Masonic- 1
-Masonic- Go!

<~napa182> !countdown 4
<&Masonic> Countdown started!
<&Masonic> 4
<&Masonic> 3
<&Masonic> 2
<&Masonic> 1
<&Masonic> Go!

on $*:text:/^([!@])countdown\s(\d+)$/iS:#: {
  if (!%count && $regml(2) isnum 1-10) { inc -u10 %count
    var %a = $v1, %b = 1, %c = $iif($regml(1) = !,.msg #,.notice $nick)
    %c 1,9Countdown started!
    while (%a >= 0) {
      $+(.,timerc,%b) 1 %b %c $iif(%a = 0,Go!,%a)
      dec %a
      inc %b
    }
  }
}

Yes I was bored...

Keep at it....

Wouldn't you be able to make an alias as such

Alias countdown {

umm I am not good at this. but do something like

.timercalc 1 1 .set %timer. [ $+[ $nick ] ] $calc( $+ $2 - 1) | .timercalcr .read %timer. [ $+[ $nick ] ]
.timercalc 1 2 .set %timer. [ $+[ $nick ] ] $calc( $+ %timer. [ $+[ $nick ] ] - 1) | .timercalcr .read %timer. [ $+[ $nick ] ]
}

So on... Now don't count me on this. but what I see it doing is a basic countdown. If you use the $2 as the begining number then have it write the number it equals as a file number. then have it read it. take it away count it down. wouldn't that work also?

Uhm i know from experience that 50/50 use . or !

About the halts. Idk why i do it its kind of my bug :P I keep hearing it but it then ruin anything though :P

@TochA1551 you should have posted this as a snippet rather than a script. also maybe name an silence your timers.
and to Bielie why all the halts? and why the 2 diff triggers ie:" ! . "? just use 1 if you are not going to use 1 for message an the other for notice.

This script has multiple things that wont work. You have to remove

You couldv used something much simpler with the same effect:

on $*TEXT:/^[!.]countdown$/Si:#:{
 if (%flood [ $+ [ $nick ] ]) { halt }
 set -u2 %flood [ $+ [ $nick ] ] $true

 if (%flood2 [ $+ [ $chan ] ]) { notice $nick Please wait 10seconds before counting down again! | halt }
 set -u10 %flood2 [ $+ [ $chan ] ] $true

 msg $chan Countdown Started!
 timer 1 1 msg $chan 5
 timer 1 2 msg $chan 4
 timer 1 3 msg $chan 3
 timer 1 4 msg $chan 2
 timer 1 5 msg $chan 1
 timer 1 6 msg $chan Go! | halt }
}

This is simple msl code but it will work better and safer then urs. I recommend using $chan for scripts that use multiple timers. Timers will cause spam and no one likes that. Unless its for fun ;D

Next time post your code in the Code section of your post.

The if ($2 > 5) { is unecesary since the script doesnt care what you type in the $2 section. It will just always count down from 5 to 0.

What you are trying to do looks like this:

on $*TEXT:/^[!.]countdown/Si:#:{
  if (!$2) { notice $nick Please provide the time in seconds you want to count down from! | halt }

  elseif (%countdown [ $+ [ $nick ] ]) { notice $nick You still have a timer running! | halt }

  elseif ($2 > 5 || $2 < 1) { notice $nick I cant countdown from lower then 1 or higher then 5! You entered $2 wich isnt correct! | halt }

  else { notice $nick Started counting down from $2. | set $+(-u,$2) %countdown [ $+ [ $nick ] ] $true | .timer $+(countdown,$nick) $2 notice $nick The timer stopped after counting down from $2 $+ . | halt }

halt
}

you can use the

for your snippet, makes it look better and easier to read.